/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*
* For more information, contact:
*
*     Vivid Solutions
*     Suite #1A
*     2328 Government Street
*     Victoria BC  V8T 5G5
*     Canada
*
*     (250)385-6040
*     www.vividsolutions.com
*/

package com.vividsolutions.jts.index.strtree;


/**
 * A function method which computes the distance
 * between two {@link ItemBoundable}s in an {@link STRtree}.
 * Used for Nearest Neighbour searches.
 * 
 * @author Martin Davis
 *
 */
public interface ItemDistance 
{
  /**
   * Computes the distance between two items.
   * 
   * @param item1
   * @param item2
   * @return the distance between the items
   * 
   * @throws IllegalArgumentException if the metric is not applicable to the arguments
   */
  double distance(ItemBoundable item1, ItemBoundable item2);

}
